The present invention relates to a novel triphenylmethane derivative which is useful as a medicament for treating osteoporosis.
Hitherto, phenolphthalin derivatives in which a carboxyl group is subjected to amidation are known. Chem. Abst., 53, 21801f (1959) discloses phenolphthalin derivatives in which carboxyl is modified to amide. Chem. Abst., 64, 19789g (1966) discloses those in which carboxyl is modified to anilide. Japanese Published Unexamined Patent Application No. 132,336/81 discloses phenolphthalin derivatives in which carboxyl is modified to methylamide.
J.C.S. Perkin I., 1978, 1211 and Archiv der Pharmazie 292, 690 (1952) describe phenolphthalin derivatives in which carboxyl is changed to amino.
In Arch. Pharm., 293, 733 (1960) are disclosed phenolphthalin derivatives represented by the following structural formula (P): ##STR2## in which R.sup.A, R.sup.B and R.sup.D are hydrogen, and R.sup.C is hydrogen, n-butyl or thioanilide; and phenolphthalin derivatives represented by the above formula in which R.sup.C is hydrogen, and R.sup.A, R.sup.B and R.sup.D represent acetyl. In Arch. Pharm., 292, 690 (1959) are disclosed phenolphthalin derivatives represented by the formula (P) in which both of R.sup.A and R.sup.B are hydrogen, and both of R.sup.C and R.sup.D are methyl or ethyl, or R.sup.C and R.sup.D are combined with nitrogen atom adjacent thereto together to form ##STR3##
It has however been not known that triphenylmethane derivatives are useful as a medicament for treating osteoporosis.